This invention relates to a lamp comprising at least one lead rod and a plurality of filaments.
Heretofore, spotlighting at a studio and a stage or the like has been performed by combining a halogen lamp with a reflector in general. FIG. 9 is a view showing a conventional example of a halogen lamp for the studio. This halogen lamp 100 comprises a base 101 and a glass tube 102 is provided on the upper of this base 101. Two pieces of lead rod 105 fixed by two pieces of glass piece 103 and 104 are arranged on the inside of the glass tube 102. The glass piece 103 fixes the upper end of two pieces of lead rod 105 and another glass piece 104 fixes the central portion of two pieces of lead rod 105. Moreover, a plurality of filaments 106 connected to each other in series is arranged between the glass pieces 103 and 104. These plurality of filaments 106 are supported by a support 108, and both ends 106a of these plurality of filaments 106 connected each other in series are connected with windings 107 wound in the form of a coil. The windings 107 are welded in the condition of being passed through the lead rods 105, thereby electrically connects a plurality of filaments 106 with the lead rod 105. When attaching the reflecting mirror to the halogen lamp 100 having a structure shown in FIG. 9 and using this halogen lamp 10, there has been a problem that the light emitted from the filament 106 is shut off by the lead rod 105, so that lack of uniformity of luminous intensity distribution are caused.
The object of the invention is to provide a lamp capable of suppressing lack of uniformity of luminous intensity distribution.
The present invention is characterized in that the plurality of filaments is arranged around said lead rod. When arranging a plurality of filaments around the lead rod, the light emitted from the filaments is irradiated approximately uniformly toward the surroundings of the lamp without being shut off by the lead rod, whereby lack of uniformity of luminous intensity distribution can be suppressed.
Here, the lamp according to the invention preferably comprises a plurality of filament structure elements, each of the filament structure elements having the plurality of filament, and the lamp comprises a plurality of the lead rod, wherein one of the plurality of the lead rod connects each of the plurality of filament structure elements. Vibration resistance of a lamp can be improved by connecting each of a plurality of the filament structure elements to the one lead rod.